I ran into the description of "mashing" on Wikipedia. There is one phrase that I think is critically wrong.

"and decoction mashing, in which a proportion of the grains are boiled and then returned to the mash, raising the temperature."

Its my understanding that boiling the grains is not good. It should read "decoction mashing, in which a proportion of the wort is removed from the mash, boiled and then returned to the mash, raising the temperature."

When you do a decoction you take the thick part of the mash(mostly grain with some water and boil it) this is done to break down the starches in non/under modified grains to get fermentable sugars. Due to modern modified malts this isn't really necessary any more but people still do it for authenticity.

Watch Kaiser's videos on mashing, he uses a strainer to get mostly grain (for the "thick" part mentioned above) and then uses a pitcher to make sure there is enough wort to cover the grains before he begins the boil. Interesting videos. It's been discussed before, why you don't get tannins from decoctions, and I don't remember all of the reasons cited, but I assume pH has a huge impact on this.

I ran into the description of "mashing" on Wikipedia. There is one phrase that I think is critically wrong.

"and decoction mashing, in which a proportion of the grains are boiled and then returned to the mash, raising the temperature."

Its my understanding that boiling the grains is not good. It should read "decoction mashing, in which a proportion of the wort is removed from the mash, boiled and then returned to the mash, raising the temperature."

You're thinking "tannin extraction", right? Tannins get extracted only if the pH of the wort are too high and then only if the temperature is high too. Normally your wort is quite acidic so decocting and boiling the mash is no problem.

"Normally your wort is quite acidic so decocting and boiling the mash is no problem."

The main mash should be soured up before attempting to boil it. Like 5.3 pH. Sauer malz along with an acid rest, or lactic acid, are used to sour up the mash in a decoction. The liquid in the mash tun is mash water. Wort is the liquid extracted from the mash during the sparging process. Sparge is terminated when the wort goes to pH 6. If the pH of the sparge water is high, sometimes phosphoric is added. If anything, wort pH will rise during sparge. Wort "Normally" becomes more acidic in the fermenter, when the yeast does its thing.